Inking and repellent system for plano-



States Patent e sYsrEMANn MnTr'ioDoF USING SAME:

wnnsnrimmuneat w naneter; Massiyassignorttt A. e. 1

Application January-14, 1953, Serial No. 331,-292 8 Clfimsa' (Cl.'101147) Thi it? for th applie on,of r epellentto the plate surface.

Ifhe rinciples underlying the-operation of a" litho-" graph c; plate are well: recognized and the same :wvhether,

invention relates to an improvement in theappli-- f e lem--10 tthexsurfa'ce-of ta'lithog'raphie auditrela-tesmore particularly to. apparav in; connection .with a -lithographicprinting press thLZplatt be formed of the old lithographic stone etched metal plate or the-more recently developed I coatedr; papenb lithogra late s r In theory; the imagedportion-of the 1 4i?"P'iwtqesrmk receptive and water repellent-Whilethe non-imaged portion formingqthe remainder of theyplate. 3

l is hydrophilio in character and-preferentially gre- I n op an aqueous repellentd's first-applied to his-generally recognized by those skilled in the ttth 'ticalzconditionsinthe operation of alitho tenan lt is believed that the basic difiiculty which: prevents any pqssihility o f' rnaintainingflthedesired balance of cond5 rece vedonly "by the imaged {portion for onto: the fofiset blanket for the production 'of er and repels the oily or greasydnk composi-; t

t rifaee oi the;.p late,- "When present in the de-. A the t repellent wets oply ,the' ;hydrophilic,- len so that greasy inks will be "repel-led tro ent systems is due in part tothe fact thatwhen' the ate dampeners are wet sufficiently to prevent anyj ei h enin form ming on the-plate moon-to thesabove; t the presentdampening system oi inlet-mm. the plate-image,-they, 'atthesame jettoo-ivet to print properly. 4 As a result it has; to strike a-compr0mise.-;In practice the form pile s vveta suliicient to prevent scumming but'not; peletheink entirelywAs a result, the damp roller becomes -progressively contaminated requ i;res -;increasing amountsof repellent to a.

is subject-1o asnumheraofother objections,;a iew -of which:

willlhereinafterg be specifically mentioned of the-.:=;=r'equirem1ent t for having the dampe properlyewet-wout--with:=repellentbefore contactf withthe I surfaqe; ofthe-plate itris-impossible-to start-operation to duce copy until several-: cycleshavebeen made:pr'opf B us g -rollers" a 2,733,653 Patented Feb. 7, 1956 2 (3) In etfect, the control through thedarnpeningsystem is limited to onedirection only Whileadditional water can be applied; whennecessary no nieans is available for cutting back on the amount of moisture on the plate -isurface other than to dissipate the excess inusegradually by cutting down on the supplyjntihthe desired"conditions are temporarily secured. In the meantime eopy- 3 poor quality is being produced (4) Ihepresence-pi the dampening .roller in contact with the lithographie surface constitutes a ,source of wear and damage tol th image and can materially affect the number of cop; which can be produced 5) Becau s e of the contamination factor andthe removal oi ink by the mol leton or dampening rollers operating in contact w ith the surf i of the p1at e,. t he;molleton covers must be replac d pr cleaned periodically and additional pres s operationsfireq required a he damrs a r n tr-pr a t1 The objectionable features of present darnpening s ys; tems which make use of a rnolletonrollereorloth I dampening f orm roller have, been substantially -com a pletely eliminated by .the nevv and improved dampening system of the type described and claimed in the Mullen Patent No. 2,60%,848, vyhieh issuedion July 2 9," 1 Brieflydeseribed the Mullen systemmakes use ofita water roll which appliesan excess of waterpnto the urface of the plate in advance of the inkinglform rolle excess moisture is removed fromvthe surface oi th by an 'air bladewhich;operatespontinuously?across I plate and may be adjusted'Qsub stantiallyfcompletely H remove the ater ;I'0I Il ih l1'nag 6$l at6a$ ofthe plate I while leaving a film of water of minimum thickness over the non-imagedareas The described Mullen-gsystenripr vidcs an exact control of moisture for each revolution Yof the plate cylinder and independently of the-amount-of moisturepresent on the surface of the plate in thejpre vious cycle. Thus it is possible-to achievet properyve ting in the first cycle of the machine for thelprodu'ction'yf of copy and it is also possible to achieve irnmediate adjustment in the amount ofmoisture ontheplatesurface without juggling the 'ratioo f water to ink asthe printing operation continues. Once the amount of moisture "f best operation hasbeen established, it is po ssible, to mai tain the desired conditions substantiallyindefinitelydu ing the operation of the machine. By reaso'n of the fact t; that the moistening roll applies an excesslof Water vvithout contact with the surface"of thejplategwear on the, plate is eliminated as, aff actor and. no ink iscapable of ff being transferred back from the surface of the Pie thereby to eliminate the p'roblemsincide'nt to; the transf of ink to the dampening roller 'as in the present systems. if Because the air blade removes all entangling Water from the dot image and establishes{essentiallya dry dot image this system] is better fadapted to the reproductiono sharper as well as full inked dots in tone andhalf-tone printing a a t v Thekdampening system of the type described differs basically from the presentsystemsfin that'it is not ,di pendent upon the amount of water repellentapplie'dt H; the surface of the plate but relies upon, the"appli ation1 of a' controllable" excess of repellent to the plate and the 4 reduction of the excess 'water "film byjadjusttnetit of pressure to provide a minimum" guantityfo'n the n printing areas and substantially complete absence of 1; moisture on inked areas at the point of contactbetwe'en the plate and the'ink form rollers. I a a a While the described air bladefsystem ffor plate'fjdarn ening provides a vast improvement in the; operation of a p e ostap fcrt nt s a e "ib s an, to i o th' invention t'o providestill j further improvements in thefi'; p n ng y entbti he 'p de ibe I .i be ic x si n' 'nfi i rov d ar mr n system of thety'pe described in which problemsin'cident United States Patent INKING AND REPELLENT SYSTEM FOR PLANO- I GRAPHIC PRINTING MACHINES Application August 14, 1952, Serial No. 304,337

6 Claims. (Cl. 101-148) This invention relates to improvements in printing or duplicating machines of the planographic type and it relates more particularly to improvements and simplification inthe process and apparatus for conditioning lithographic plates for printing.

In lithographic printing, the lithographic plate having an ink receptive and water repellent image anchored onto the ink repellent and hydrophilic surface is first engaged by a repellent applicator for wetting the non-imaged portion of the plate and is then engaged by an ink roller for applying ink composition which is received only by the imaged portion of theplate and repelled by the non-imaged portion. In direct printing, the inked plate reproduces the image on the surface of the copy sheet when pressed against the surface of the plate by means of a platen roller or the like. In indirect or offset printing,

the inked plate is engaged by an offset blanket for transfer of the ink in mirror image to the surface thereof and from which the transfer is reproduced as a direct image onto acopy sheet as it passes under compression between the offset blanket and a platenroller.

'In a rotary duplicating machine of the offset or direct type, the lithographic plate i s mounted on a cylinder or drum. A repellent system is provided for applying the aqueous repellent to the surface of the plate in a desired amount and a separate ink distributing system is provided for applying a uniform and desired distribution of ink ontothe surface of the wetted plate for inking the imaged area. 'It is necessary to provide "means for adjusting the concent'ratiodof ink and achieving a desired distribution of inkin order to producecopy of good quality and it is also necessary-to providemeans for adjusting'the amount of repellent applied to the surface of the plate and to balance the'amount of repellent and ink for continuous operation. If the amount of repellent is insuflicient, the lithographic plate or master will tone or ink up and ink will be caused to transfer to areas other than those that are im-' age'd'and produce undesirable copy. If the amount of repellent is excessive, then the imaged portion will become wet and spotty and imperfect copy will result and emulsififatio'nmay also take place to prevent subsequent use of the ink composition. The repellent system in general used to the present includes a ductor roller which periodically reciprocates back and forth between a roller submerged in a bath of repellent'and a molleton roller positioned to engagethe surface of the lithographic plate. The repellent roller turns slowly-in the bath and transfers aqueous repellent from the surface thereof to the ductor roller upon contact. The molleton'roller is provided with a molleton cover in the form of a cotton sleeve or the like for absorbing the repellent from the ductor roller and distributing same over the surface'for transferring uniform concentrations to the surface ofztheplate. Because of the'in'k remaining on the imaged portionof the plate, the molleton roller soon becomes loaded with ink composition to the extent that periodic replacement is-necessary for desired operation.

2,733,654 Patented Feb. 7, 1956 ICC It will be apparent that the separate systems for applying ink and repellent, the controls necessary to regulate the amount and distribution thereof, and the systems for spreading the ink and repellent over the respective rollers of the systems require the use of considerable equipment, space and necessitate the employment of expert labor in order to succeed in the production of copy of good quality. These requirements handicap the utility of prior machines and their adaptability for use in office duplication work and it is a general object of this invention to overcome the objectionable characteristics of the present machines.

It is an object of this invention to produce a plane graphic printing machine ofthe type described which is more adaptable to oflice copy work and it is a related object to produce a machine of the type described which is more compact; which is simple in operation; which provides for simple and expedient adjustment for balancing the amount of repellent and ink; which eliminates the need for skilled labor in order to produce copy of good quality, and which eliminates many of the time consuming and undesirable operations characteristic of ink and repellent systerns of the type heretofore employed.

A further object is to produce a rotary planographic duplicating machine embodying a new and improved system for transfer of repellent to the surface of the lithographic plate and it is a related object to provide a repel: lent system of the type described in which the amount of repellent advancedto the plate may be easily and quickly adjusted to provide a simple and expedient control and in which replacement of a molleton is avoided thereby to eliminate the nuisance, dirt and effort characteristic of present repellent systems.

A still further object is to provide a lithographic duplicating machine of the type described in which ink and repellent are applied from a single system without noticeable emulsification and which embodies means for easily and quickly adjusting the amount of ink and repellent advanced to the plate for maintaining the desired balance required for continuous operation in, the production of copy of good quality.

These and other objects and advantages of this invention will hereinafter appear and for purposes of illustration, but not of limitation, an embodiment of this invention is shown in the accompanying drawing in whichof a rotary lithographic machine embodying features of this invention;

Figure 2 is a sectional elevational view taken substantially along the line 22 of Figure 1, and

Figure 3 is a schematic elevational view of the repellent rollers, taken as indicated by a line 3-3 in Fig. 2.

Description will now be made of an assembly embodying the features of this invention for use in a conventional type of rotary lithographic press suitable for office use in the production of copy from metal or paper lithographic plates by direct or offset technique. It will be understood that the features of this invention are equally applicable to larger installations for the production of copy by lithographic process. As shown in the drawing, 10 indicates a framework for the machine including upright side walls 11 and 12 between which a master or plate cylinder 13 of relatively large diameter is mounted for rotational movement with shaft 14 Means are provided, such as clamps 15 and 16, for mounting a lithographic plate 17 about the periphery of the drum 13 and on which the desired image has been formed for they production of copy. Apparatus of this character usually has'another cylinder of substantially equal dimensionfor mounting an offset blanket incont-acting relation with the plate during turning moverrie'ntto enable ink" in the imaged portion of the plate to be transferred in reverse, onto the blanket and 'then' onto' copy sheets as suchcopy M ws.

plate mounted for-movement inone direction on a sup? crosswise of and in closely spaced relation withth'e surface 7 of the plate, said air nozzle being positioned'to direct the streamof' air as afcontinous air blade onto the surface of the plate at an angle of less than zero but greater than. 30 with the normal to the plate whereby the excess repellent on the'surface of the plate and repellent on theimagedportionsthereofis displaced r'earwardly onto theoncoming portions'of the plate, means for removing the'repellent' displaced rearwardly ontothe plate comprising a housing having an ,inlet opening aligned with the outlet 'openin'gof the'air n'ozzzle and inclosely spaced parallel relation therewith and in closely spaced relation with the plate surface to'remove repellent displaced rear-wardly 'onto'the surface of the plate, means for introducing air into "the air nozzzle for passage through theoutlet'opening as an air stream of high velocity, and means for withdrawing air from the suction housing to withdraw repellent through the inlet opening from the surface of the plate.

4. Adampening system as claimed in claim 3 which includes means for adjusting thepressure of the air introduced into the blade housing to adjust the pressure of airi'rr the air lblade extending across the surface of the plate.

5. A dampening system as claimed in claim 3 in which the air nozzle is positioned to direct the airhlade' onto the plate at an angle between- 10" and -30."

6. The method of dampening a planographic printing plate bythe use of apparatus of the type described which comprises moving the printing plate continuously in one direction, applying a liquid repellent onto the surface of the plate in excess of the amount required for use in the printing operation, directing 'a stream of air which extends continuously crosswise of the plate as a blade onto the surface of the plate at an angle less' than zero but greater than +30" with the normal to theplate whereby the port,means for applying an'excess of liquid repellent onto the surface of theplate and means for removing" repellent excess repellent. onthe non-printing portionsof theplate andlrepellent on the imaged portio'ns isdisplaced rear wardly ontotheplate' fronrthe line of management the 'air blade and the plate and removing repellent di's'-' placed rearwardly "onto the'plate'by suctionmeansfhaving itsinlet opening aligned with the blade and positioned immediately rearwardly thereof. 7 V I 7'. The method of dampening a' planographicprinting plate by the use of apparatus of. the type described which comprises the steps of moving the plate continuously in one direction, applying liquid repellent onto the surface of the plate in excess of the amountjrequiredf foruse in the printingoperation,directing a stream of air ex f tending continuously crosswise of the plate as ablade' onto the surface of the plate from an air nozzlehaving its exit opening extending continuously crosswise'of the j 1' plate and positioned "to direct the air stream onto the blade at an angleless than zero but greater than, l-.30" to the normal of the plate whereby the'excess repellent. on the non-printing portions of the plate, and repellent on f the imaged portions is displaced rearwardlyfrom the point of contact, and removing repellent displaced rearwardly onto the plate by suction means through a housing having its inlet opening co-extensive with an aligned with the I exit opening of the nozzle and spaced immediately rea'rwardly thereof, introducing air into the nozzle forissuance under pressure from the exitopening as a continuous blade, and withdrawing air from the housing to such the excess repellent displaced rearwardly by the blade through the inlet opening into the housing for removal.

8, The method as claimed in claim 16 in which the air nozzle is' positioned to direct the stream of air as a blade j onto the surfaceot the plate at an angle between '10 and with the'normal.

References Cite d in the file of this patent UNITED STATES PATENTS 2,139,628 Terry Doc. 6,1938 J 2,366,926 Melton Q. Ian. 9, 1945 2,590,429 Ras .Mar. 25, 1952 2,604,848 Mullen July 29, 2 2,679,231 Pomper et al. L ...L May 25, 19 54 '5 repellent topass as a spiral film with the rollers through the nip for transfer from roller 31 to the form roller.

The amount of repellent carried through the nip depends upon the pressure between the rollers, as previously pointed out, and the frequency of such amounts being carried through depends upon the number of droplets or the frequency of droplets traveling down the incline. Thus two separate and distinct means, each of which may be accurately and quickly adjusted, are available for varying the amount of repellent that is advanced to the form roller and onto the lithographic plate.

' By increasing the frequency of droplets, the amount repellent may be increased and by adjustment of valve 48 to decrease the number of droplets, the amount of re pellent fed to the lithographic plate may proportionally be decreased.

By screwing inthe bolt members 36, the pressure between rollers is increased to cause a proportional decrease in the thickness of the film of repellent that remains on the inner roller 31 for transfer to the form roller. Loosening of the bolts permits the outer roller 30 to shift outwardly and increase the amount of repellent which is fed to the lithographic plate. It will be understood that the pressurebetween the roller 31 and the form roller 26 is kept suflicient tomaintain surface contact between these rollers, despite the inclination of the rollers 30 and 31 relative to the horizontal axis of the form roller. It will also be apparent that by travel of the droplets from one end to the other in the crotch between ink rollers, repellent will have been applied uniformly through the length of the roller. Thus it is possible by the greatly simplified system described herein to secure uniform application of repellent and to achieve accurate and rapid adjustment for maintaining the desired balance of ink and repellent for continuous operation. When the amount of repellent is intentionally reduced to cause the plate to tone, normal conditions for good duplication can be quickly restored by increasing the feed rate of repellent and the excess ink on the surface of the plate is completely and quickly removed.

It will be understood that the concepts of this invention which provide for a quick and easy adjustment of repellent to ink composition and which eliminates many of the undesirable features, expense and space requirements of prior processes may be embodied in lithographic machines of different types wherein ink and repellent are required to be supplied to the printing surface in varying but predetermined proportions.

It will be further understood that instead of mounting the repellent rollers 30 and 31 for transfer of repellent directly to the form roller, or as previously pointed out to distributing rollers for ultimate transfer to the form roller or plate, the repellent rollers may be adapted to contact practically any roller in the ink distributing system for transfer with the ink to the form roller or the plate, and that other changes may be made in the specific means for adjusting the spaced relation between rollers and for supplying the repellent dropwise to the crotch between the repellent rollers without departing from the spirit of the invention, especially as defined in the following claims.

I claim:

1. Apparatus for applying ink and repellent to a planographic printing plate mounted on the periphery of a horizontal rotating drum comprising a form roller mounted for rotational movement about a horizontal axis and in 6 of said form roller, means for feeding repellent in drops into the crotchat the higher end in excess of the amount to be transferred to the form roller whereby drops travel down the crotch during rotation of the repellent rollers, and a contacting relation between one of the repellent rollers and the form roller to transfer repellent passing through the crotch to the plate.

2. Apparatus for applying ink and repellent to a planographic printing plate mounted on the periphery of a horizontal rotating drum comprising an ink train including a series of inking rollers mounted for rotational movement about horizontal axes for supplying ink in uniform distribution to the plate, means for feeding repellent to 'said ink train for transfer with the ink to the plate comprising a pair of repellent rollers mounted in side by side relation to form a crotch therebetween with one of the repellent rollers in surface contact with one inking roller in said train, means mounting one end of the repellent rollers at a higher level than the other to provide a gradual tilt of said repellent rollers relative to the horizontal axis of said one inking roller, and means for feeding repellent into the crotch at the upper end of the re- Ipellent rollers whereby the repellent travels down the crotch during rotation of the repellent rollers and some of the repellent is carried through the crotch for transfer to the one inking roller and to the plate.

3. Apparatus for applying ink and repellent to a planographic printing plate mounted on the periphery of a rotating horizontal drum comprising an ink train having a series of inking rollers mounted for rotational movement about horizontal axes for supplying ink in uniform distribution to the plate, means for feeding repellent to said ink train for transfer with the ink to the plate com prising a pair of repellent rollers mounted in side by side relation to form a crotch therebetween with one of the repellent rollers in surface contact with one of said inking rollers, means mounting one end of the repellent rollers at a higher level than the other to provide a gradual tilt of said repellent rollers relative to the horizontal axis of said one inking roller, means for feeding repellent in drops into the crotch at the upper end of the repellent rollers in excess of the amount to be transferred to the inking roller whereby the drops travel down the crotch during rotation of the repellent rollers and some of the repellent is carried through the crotch for transfer to the inking roller and to the plate, and means for adjusting the rate of dropwise feed of repellent into thecrotch between the repellent rollers thereby to adjust the frequency of the drops and correspondingly the amount of repellent which pases through the crotch to the inking roller.

4. Apparatus for applying ink and repellent to a planographic printing plate mounted on the periphery of a rotating horizontal drum comprising a form roller mounted for rotational movement about a horizontal axis and in surface contact with the plate, means for supplying ink in uniform distribution to the form roller, means for feeding repellent to said form roller for transfer with the ink to the plate comprising a pair of repellent rollers mounted in side by side relation to form a crotch therebetweenwith one of the repellent rollers in surface contact with the form roller, means mounting one end of the repellent rollers at a higher level than the other to provide a gradual tilt of said repellent rollers relative to the horizontal axis of said form roller, means for feeding repellent in drops into the crotch at the upper end of the repellent rollers in excess of the amount to be transferred to the form roller whereby the drops travel down the crotch during rotation of the repellent rollers and some of the repellent is carried through the crotch for transfer to the form roller and to the plate, and means for adjusting the other repellent roller in the direction toward and away from the one repellent roller in surface contact with the form roller to vary the pressure between the repellent rollers and thereby correspondingly to adjust the amount ing a series ofinking rollers mounted for rotational mover nent about horizontal axes forsupplying ink in uniform distribution to the plate, means for feeding repellent to said ink train for transfer with the ink to the plate comprising apa'ir of repellent rollers mou'ntedin side by side relation to form a crotgh therebetween 'with one of the repellent rollers in surface contact with one inking roller insaid train, means mounting one end of the repellent rollers ata higher level than the other to provide a grad ual tilt of said repellent rollers relative to the horizontal airis of said one inking roller, means for feeding repellent l5 in;drops into the crotch at the upper end of the rollers in excess of the amount tojbe transferred to the ink train whereby the drops travel down the crotch during rotation of the repellent rollers and some of the repellenta is carried through the crotch for transfer to the ink train and to the plate, means for adjusting the rate of dropwise feed of repellent into the crotch between therepellent rollers thereby to adjust the frequency of the drops and correspondinglythe amount of repellent which vpasses through the crotch tothe ink train; and means for adjusting the other repellent roller in the direction toward and away from the one repellent roller in surface contact. with said one inking roller to vary the pressure between the repellent rollers and thereby correspondingly to adjust the amount of repellent carried through the crotch to the ink train. a

6. Apparatus for applying ink and repellent to a planegraphic printing plate mounted on the periphery of a rotating horizontal'drum comprising an ink train including aseries of inking rollers mounted for rotational movement about horizontal axes for supplying ink in uniform distribution to the plate, means for -feeding repellent to said ink train for transfer with the ink to the plat'e comprising a pair of repellent rollers mounted in side by side relation to form a crotch therebet-ween with one of the rollers in surface contact with one inking roller in said train, means mounting one end of the rollers at a higher level than the other to providea gradual tilt of said repellent rollers relative to the horizontal axis o'ffisaid one inking roller, means for feeding repellent in drops into the crotch at the upper end of the repellent rollers in eiteess of the amount to be transferred to the ink train whereby the drops travel down the crotch during rotation of the repellent rollers and some of the repellent is carried through the crotch for transfer to the trair 1 and to the plate, and a drip pan underlying the repellent rollers for collecting the excess repellent which drains from the crotch.

References Cited in the fileof this patent UNITED STATES PATENTS 7 

